Braking system



w. s. H. HAMILTON BRAKING SYSTEM v Mg -ch '15 {1927. 1,621,403

Filed June 4, 1925 I 5 Sheets- Sheet 1' Ali Inventor: Wiliiam S.H.H'ami it on,

His Att. or-neg.

March 15 1927. 1,621,403

w. s. H. HAMILTON BRAKING SYSTEM Filed June 4; 1925 3 Sheets-Shoot z Inventorz William S. H. Hamilton His Attorney.

March 15 1927..

w. ;H. HA N BRAKING SYSTEM Filed June 4, 1925 3 Sheets-Sheets Inventor-1 \Afiliiam S. H. Hamilton,

' His Attorney.

Patented Mar. 15, 1927.

Hams Tor, or SCHENECTADY, new am; Assam- 11 r6 ELECTIRiC COMPANY, A oonrorie'rion or new Yonfi';

BitAkI'NG SYSTEM;

Ap 'iicatim filed June 4, 1925. Serial m. 34g967;

This'invention relates to braking systems for electric railway 131111115 which are provided: WltlrbOtli air braking means, and electrio braking means.

The object of the invention is to amplify theinterlocking between the air brakes and the electric brakes beyond that wh'iclrhasbeen provided in systems now in use in ordeiito permit moreflexible and smoother handling of the electric locomotive and train; 1

Ithas'been-propos'ed heretofore to inter lock pthe air and electric brakes on an e'lectrio locomotive or the like 'so as to permit the selective operationoi: either theairorthe electric brakes/while, preventing the simultaneous application thereof, except in cases} of emergency; Under some service conditions, however, it isadvantageousto allow a certain amount of electric braking to be obtained on the locomotive before the air brakes" are out off and alsoto permit a limited applicationof the"l ocomotive air brakes beforelthe' electricbraking is di'scon tinued or'de'r' to facilitate handling the train, as forexample,-whenstarting or stop-'7 ping tl-ie tra-inon a-grade. Likewise, where the electric locomotiveis provided" with sepa-- rately operable air and electric brakes andthe cars drawn byjthe locomotives are provide'd only with the'usual air brakes it is desirable to permit automatic control of the airbrakes" on the cars as well-as the 1000- motive while coordinating-v the air and electric brakes on the locomotive so-as to insure that-the combined air and electric braking-- onthe" locomotive never exceedsthe valuerequired to slide the wheels when the air brakes on the cars are applied although per mit-ting independent application of thelOcomotive airbra kes to full value at the willof'the engineer at anytime.

The above desirable results among others may be obtained by means of my invention which;- in general, provides the following features:

1; The-locomot veair andelectric brakes m'a'ybe simultaneously applied and the combinedbraking effect isautomatic-ally main tained at 2; maximum value which 1 will I not slip the wheels of the locomotive, although the relative proportion of air an'd*electric brakingmay be varied;

2.-If the electric brakes on the locomotive fail the air brakes'are' automatically appliedat full" value: y I

'3. In case aservice application" of the car air brakesfism'ade when" the locomotive electric brakes are applied, the locomotive air brakes are applied auto1nat'ically when the electric'braking is reduced below a certain value."

4'. Inemergency fullvalue of air braking may be ajqn'olied' to the locomotive andthe cars and the electric brake is rende'red in:

operative. v I v.

vIn'oarr'ying'the invention into'efiect-in a" preferred'form an electrically controlled air' operated piston is provided for controlling theoperat iori of the'distributing valve which ordinarily reflects the application of the air brakes-on the loc'omo'tive when a serviceapplicationof' the air brakes onathe cars is made so thatwhen. the locomotive electric brakes are applied; above a certain value, the airbra'kes on the locomotive are not applied:

Theairoperated' piston is electrically con-' trolled; by the electric. braking ,controh mechanism sofas'to automatically effect the brakes on the'loc'omotive' should fail at-an-ytimjey v I c. a p The invention willbe. better understood by reference'to-the accompanying drawings in which Fig. 'LdiagrammatiGally shows abrakin'g' system for an electric locomotive andthe carshauled thereby embodyingthe i invention; Fig: 2 showsza= modification! of-thesystem illustrated in Fig; 1; and Fig; 3 shows a similar braking system embodying a-utomatic 'mean's for maintaining the coinbined air 1 and electric braking effect 0Il 'tl1' locomotive at a predetermined value.

Referring to Fig.1]1 of the drawing; the

, driving motors of the locomotiveycompris 1 ingrthe armatures A 1 Q ,-'and'theseries field windings F F are arranged to be over excited by the exciter generators G G respectively to effect regenerative electric braking of thelocornotive. The exciter generators are arranged to be 'ClI'lVGIl preferably at constant speed, by means not shown in the drawing, such asan electric motor. The V serles fields S S of the exciter generators G G respectively are connected to be energized by the generated current of the motors A A while the exciter generator shunt fields f f are connected to receive current from a suitable low voltage source such as the'battery B through the regulating resistance R which may bevaried by the opera 'tion of the electromagnetic contactors C under thecontrol of the controller Br. 0.

s It will be observed that the drlvmg motors A A of the locomotive are connected for series and parallel motoring and regenerating operation by means of suitable electromagnetic contactors C C G which are arranged to be operated under the control of the main controller M. G. and the braking controller Br. C. in a well known manner. 7

The air brake system shown in the drawing is arranged to control the application of the air brakes on the electric locomotives, as well as on the cars-drawn thereby. The braking cylinder B. C. applies the locomotive .air brakes and a plurality of braking-cylinders similar to the cylinder B C apply the carair brakes. Airis supplied to the main reservoir M. R. by an air compressor or other suitable means not shown and the equalizing reservoir E. R. is 'providedfor controlling the emergency and service application of the air brakes on both the locomotives and the cars in the usual manner. The manual control of the air brakes is effected by means of two valves, one being i the engineers independent valve 10 which controls the application of theair brakes on the locomotive, but not on theremainder of the train and the other being the engineers automatic valve 11 which controls the appliv cation of the brakes on both the locomotive 7 from the auxiliary reservoir A. R. to the braking cylinder 13,, G with which each of the cars in thetrain may be provided;

' The distributing valve D V. has a piston 1 for operating the. application valve 15 which controls the admissionof air from the main reservoir through the pipe16, the passage 17 and the pipe 18, to the locomotive braking cylinder B. C. The admission of air from the pressure chamber P. O. to

the application cylinder in which the piston 14% operates is under the control of the" equalizing valve 19, which ispperatiVely connected with the equalizing p1ston20, so

as to be operated responsively toa decrease in the pressure in the train air-line 13 in the well known manner. 1

In order to prevent operation of the application valve 15 when the electric brakes are applied on the locomotive Iprovidethe distributing valve with an auxiliary piston 21 which is mechanicallyconnected to o pose the application piston 14. The admlttance of air from themain reservoir M. R.

to the right hand side of auxiliary piston 21 locomotive, the auxiliary contacts 25 associated withthe engineers independent valve 10 and the auxiliary contacts'26 which are closed when the line circuit breaker L. B.

in the locomotive motor circuit is closed, the contact segments 27 of the braking controller Br. (3., as well as the contact seg-" ments 28 of the main controller M. C. The auxiliary contacts 25 are arranged to be closed when the independent valve 10 isin elther the released or the runnlng positions r r, and opened in the lap or application 7 positions 1, a a respectively. The auxiliary contacts 27 on the braklng. controller are closed only after the controller has been;

operated to apply a certain amount of elec tric braking to the locomotive as, for example, to the 4th-operatii1g position asindicated in the drawing. -These, several auxiliary contacts insure that the valve. 22 remains in the position in which it is shown until after a certain amount of electric braking has been applied to the locomotive. This permits the distributing Valve 1). V. to be operated automatically to apply the locomotive air brakes upon a service appli cation of the car air brakes by the'engineers automatic valve 11 or by operation of the engineers independent valve .10, as will be more fully pointed out hereinafter. 'However, when the braking controller 27 is operated beyond its third position to increase the electric braking the energizing circuit of electromagnetic valve 22 is com- 7 though pressure is admitted to the left-hand side. of the application piston 14' through operation of-the equalizing valve 19 respectively'to movements of the engineers automatic valve 11. Should thebraking' controller be returned to the third position to reduce the amount ofelectric braking on the locomotive the electromagnetic valve 22 is deenergized and returns to. the position in which it is shown to exhaust pressu'refrom the right hand side of auxiliary piston 21 and thereby permit the pressure which may be applied to the left hand side of application piston 14 to operate the application valve 15' so as to supply pressure from the main reservoir through the pipes 16 and 18 tothe braking cylinder B. C. and automatically reapply the locomotive air brakes.

In order to automatically apply the air brakes on the locomotive in case electric braking should fail for any reason, the electromagnetic valves 29 and 30 are arranged to'beenergized to respectively admit pressure to the application pipe '12 and close the release'pipe 31 Briefly, this is accomplished through the agency of the auxiliary contacts 32-which are closed when the locomOE tive line breaker L. B. is open asindicated in the drawing and the lower auxiliary contacts 25 on the engineersindependent valve 10 which are-closed only when the valve is in the running position r Emergency application of the car brakes made by means of the engineers automatic valve 11 causes the locomotive air brakes to be applied at full'value and also renders the electric brakes inoperative by operation of the pressure responsive device 33. As

shown, the pressure device 33 is arranged to mechanically latch the switch- 3 1 in the closed position and is connected through the pipe 35 to respond to operation ofthe automatic engineers valve 11 to the emergency position and release the switch 34.

'usedwhen the train is proceeding onxa down grade is simple andwill readily be understood by those skilled in the art from the following description. In order to apply-the regenerative braking, the main conand the troller C. is operated to. connect the motorsin eitherseries or parallel relationand control the electromagnetic cont'actors' C C to remove a desired amount of the resistors Ra, R from. the motor circuits The braking controller Br. CJthen is moved into. a selected one of its operating positions to operate the electromagnetic switches G to connect the exciting" generators G5, G tothe motor series fields]? and F1 and to: operate the electromagnetic contactiors G toproduce a desired. excitation of the eXciter shunt field windings f f Under these conditions the series fields F F of the motors are excited beyond the normalz value'and developin the motors a cotimer-electromagnetic force suffi- .cient to return current to the trolley'lin'e '1,

and. thereby'exert an electric braking effect upon the locomotive.

lVith the braking controller 1313C. inieith'er of its first three operating positions only a limited amount of ele'ctricbrakingr: will: be obtained. Underthese' conditions theeneri gizing circuit of the electromagnetic valve 22 is interrupted at the contact segments 27 of the braking controller and theright hand side of: the auxiliary piston 21 isconnecte'd to the braking cylinder B. G. throughthe pipe 23. Thusif the engineersautomatic valve 11 is operated togreduce the pressure in the train air line 13 to cause the triple valve T. V. onthe cars to admit air from the auxiliary reservoirrA. Rato the appli'ca car air brakesatlre. distributing "valve D- V. operates to simultaneously apply the air brakes on the locomotive in the following manner; Upon reduction: of the :pressure in the train air line 13 the' air which previously has been admitted to the pressure chamber P. 0. through theleakage groove-37 moves the equalizing'piston: 20 t'o'theright beyond the leakage groove 37.' This operates the equalizing valve 19 to the right toipermit the 7 air in pressure chamber P. G. to expand into the application chamber A C. and at the same time pass through-the passage 38'to the left'hand sideof application piston 14 until equalizati'on of the-pressures on theopposite sides of piston 20 occurs. Piston i l re 'tion' cylinder B C and thereby apply the r sponds to the pressure admitted into the appressure line16,"the passage 17-, orifice .39..

. chamber 40, and thepipe 18. Vvhen theiair pressure applied to the braking cylinder B. G. and also exerted uponth e rightliand side of application piston 14 exceeds the pressure applied to the left hand side of the piston 14, the latter is movedslightlyto the left to close theapplicati on valve 1'5 'l hus &

;the pressure supplied to the locomoti've'brakthe valve responds to admit full pressure from the main reservoir M. R. to the right hand side of auxiliary piston 21. Since the 'full reservoir pressure upon the auxiliary piston 21 exceeds the reduced pressure upon the application piston 14 the latter'is moved to its extreme left hand position and opercation between the'brake cylinder B. C. andates'the exhaust valve 41 to open communiatmosphere through the passage 42 and thereby release the air brakes on the locomotive.

Ifnow the regenerative braking of the locomotive should fail due to either an excessive-overload current or an over-voltage,

such as may occurupon a failure of the source supplying the trolley T, the former causing the line. breaker instantly to open and the latter causing the over-voltage relay 43 to interrupt the circuit of the holding winding 36' and thereby open the line breaker, the air brakes are automatically applied onthelocomotive at full value in the following manner. The opening of the line breakeropens the energizing'circuit of the electromagnetic valve 22 at the contacts 26 and closes the energizing circuit of the electromagnetic valves 29 and 30 at the auxiliary contacts 32. Upon the deenergization of the electromagnetic valve 22 the main reservoir pressure is exhausted from the right hand side of auxiliary piston 21 through the.pipe 23 into the braking cylinder B. C. Thus when the electromagnetic valves 29 and 30 respond respectively to admit pressure from the main reservoir through the reducing valve 14; to the application pipe 12 and at the same time close the release pipe 31,-the application piston 14 is subjected to its full normal pressure and moves to the right to establish communication betweenthe main reservoir M. B. and the locomotive braking cylinder B. C. through the pipe 16, the passage 17, chamber and the pipe 18.

WVithfull main, reservoir pressure applied a to the locomotive brakin cylinder B. C. the

locomotive air brakes are applied automatically at full value to prevent the locomotive from pulling away from the train upon If it is desired to eliminate the operation of the valve 11 bythe engineer upon a failure of the GiGCtIlO regenerative braking, the simultaneous application of the air brakes on the cars and the locomotive may be automatically effected by the arrangement shown in Fig. 2. This is accomplished by providing the electromagnetic valve 30 for closing the release pipe 31 in the manner previously described, and also providing an electromag- -net1cvalve 16 for controllmg the admission of air from the main reservoir M. B. through the feed valve 417, the pipe as and the valve 11 to the train air line 13. It will be understood that the feed valve 47 automatically maintains the proper pressure in thetrain air line and that the equalizing reservoir E. R. is normally connected to the train air line 13 when the engineers automatic valve 11 is in the running position 73. A second electromagnetic valve 19 having its operating winding connected to be energized in parallel with the operating windings of valves 30 and 46, is arranged when energized to exhaust air from the equalizing reservoir E. B. into the storage reservoir S. R. and thereby reduce the pressure in the train air line 13 a predetermined amount, preferably an amount'suthcient to effect a heavy service application of the car air brakes. It will be observed that the energizing circuit for the electromagnetic valves 30, 46 and 4:9 extends through the auxiliary contacts 50 on one of the contactors C and the auxiliary contacts 51 associated with the engineers automatic valve 11, aswell as the auxiliary contacts 32, which are closed when the line breaker L. B. is opened. The auxiliary contact 50 is closed when the contactors C are closed to establish the electric braking connections of the locomotive, while the auxiliary contact 51 is closed only when the engineers automatic valve 11 is in the normal running position 1' 1 I The auxiliary piston 21 and the electromagnetic valve 22 serve to prevent operation of the distributing valve D. V. to apply the locomotive air brakes when the'braking con troller Br. C. 1s beyond a predetermlned operating position in exactly the same mannor as previously described in connection with'Fig. 1. Thus, while the. electric regenerative brakes are applied beyond a certain value on the locomotive, a service application of the car brakes cannot effect application of the locomotive air brakes. However, uponfailure'of the electric braking the air brakes on both the cars and the locomotive are simultaneously applied in the following manner. Upon opening of the line breaker L. B. responsively to a failure of electric braking, the electromagnetic valve 22 isdeenemized upon theopeningwof the auxiliary contacts '26 and the electromagnetic valves 46 and 49 are energized-upon upon the locomotive when the electricbrak* ate the equalizing valve 19 to exhaust the air from the pressure chamber PC. into the application chamber A. C. :The air pressure in application chamber A. C. is applied to the left hand side of application piston 14 through the passage 38, since the release pipe 31 is closed by valve 30. This causes movement of the application piston 14 to admit pressure from the main reservoir M. R. to the locomotive braking cylinder B. C. through the pipe 16, the application valve 15 and the pipe 18', as previously described.

The braking efiect of the locomotive and car air brakes ordinarily will exceed the electric regenerative braking effect previously exerted by the locomotive, and hence Will serve to maintain the speed of the trainwithin safe limits.

The pressure responsive device- 33 shown in Fig. 2 renders the electric braking inoperative on an emergency application of the train air brakes in the same manner as previously described in connection with Fig. 1

The braking system shown in Fig. 3 embodies the electromagnetic valves'29' and previously described in connection with 1, for automatically applying the air brakes ing fails, as Well as the pressure responsive device for rendering the electric brakes inoperative upon an emergency application of the air brakes on both the locomotive and the cars of the train and, in additiomis provided with automatic means for maintaining the combined air and electric braking eiiec'ti on the locomotive at a suit-ablevalue which The automatic will not slip the wheels. means in the system lllustrated' comp-rise essentially the electromagnetic valves 52 and 53, together with the relay 54. The valve 52- -is'nor1nally biased to admit air from the right hand side of the auxiliary piston 21 to the air line 18 of the braking cylinder B. C., \vhilethe valve 53 is normally biased. to cut off communication between the main reservoir M. R. and the right hand side of piston 21. The relay 54 is arranged to be operated responsively to the combined air and electric braking eiiect on the locomotive. This ing.

is accomplished'by connecting alepiston 55 which is at all times responsive to the pres sure in *the air liine'of the braking cylinder B. Cl,-a'n'd hence is operated in accordance operates on the welllznown wattmeter principle and has one winding 57 energized r-e-' sponsiv'ely to the regenerated "current of the motors. A second winding 57 of 'the actuating mechanism is connected across the series field Winding F of one of the motors to be energized responsively to the field current of the motors. If desired, a regulating resist since 59 may be connected in circuit with the winding '57" as shown in the drawing to permit calibration of the actuating mechanism. The movable controlling member 56' of the relay is biased out of engagement with the stationary contact segments "60, 61, (SQ-by means of the spring 63, the tension of which may be adjusted by means of the adjusting screw 64. p

The automatic relay 54 separately controls the energizing circuits of the electromagnetic valves 52 and53- which extend from the battery B through the contact segments 28 of the main controller M. "(3., segments '27 of the braking controller Br. CfauXiliary contacts '26 on the line breaker B. and the auxiliary contact 24 of one of the electromagnetic contactors C 'Thus when the main cent-roller M, C; is operated to close the line breaker L. 13.3.1161 establish series 'or parallel connections of the motors and the braking controller BrxC. is moved into a desired brakingpositi on to close the electromagnetic contactor (1 and control the energization of the. shunt field-windings f 73 by operation ofthe proper cont-actors C to effect regenerative braking operation of the locomotive, both of the windings 57 and- 57 of the electric actuating mechanism 57 are energized. The actuating mechanism 57 thus exerts a torque upon the movable contact :arm 56* proportional to the value or the torque exerted by the traction mo tors of the locomotive during electric brak- It now a service application of the train air brakes isma-de by moving theengineersautomatic valve 11, air is admitted from the pressure chamber PC. to the applica-tion chamber A. C. and also'to the left hand side of the application piston 14 of the distributing valve D. V. as previously described. Piston 14 responds to move the applicationvalve 15 to admit air from the main reservoir through the reservoir pressure line'16, the-passage 17, tothe air pipe:

locomotive. As previously pointed out, the piston 55 is responsive to the pressure in the braking cylinder air pipe 18, and consequently exerts a force upon the contact arm 56 in the same direction as the electric actuating mechanism 57. If the added force of the piston 55 which corresponds to the amount of air braking on the locomotive is 7 sufficient to move the contact arm 56 into engagementwith the cooperating segments 60 and 62, thus indicating that the combined lishes a circuit from contacts60 through the coil of valve 53 in parallel with that of coil 52. The valve 53 operates to open and admit air from the main reservoir M. Rl, valve 53, the pipe 58 to the right hand side of piston 21. This'causes a pressure to be built up on the right hand side of piston 21 greater than that on the left hand side of piston 14. Consequently, piston 21 moves the valve 15 toward the left shutting oii the connection from main reservoir M. B. through the pipe 16, passage 17, valve '15, passage 40 and pipe 18 to the braking cylinder B. C. Valve 15 in its movement uncovers passage 42 and permits air to exhaust fromthebraking cylinder B. (1, pipe 18, valve 15 and passage 42 to atmosphere, thus causing a reduction in the pressure in braking cylinder B. C. and on the piston 55 of device 54. When the pressure against piston 55 is reduced suiiiciently, the spring 63 pulls the movable contact 56 out of engagement with the contacts 61, thus deenergizing the valve 53, which in turn closes the connection between the main reservoir M. R, valve- 53, pipe 58 and the right hand side of piston 21. Thisileaves a certain amount of air pressure trapped in thechamber on the right hand side of piston 21 and this pressure is opposed by the pressure on the left handside of piston 14. This will-result in valve 15 moving toward the 'right'suiiiciently to close the passage between pipe 18, passage 42 and atmosphere. Under this condition the pressure in the braking cylinder B. C. is substantially the difference between the pressure on the left hand side of piston 14 and the pressure on the right hand side of piston 21. The pressure inthe' braking cylinder B. G. is sufi'icient through action on piston 55 to cause the movable arm 56 to remain in contact with contacts 60 and 62.

If new the braking controller Br. C. is

operated to decrease the electric braking on the locomotive, the torque of the electric actuating mechanism 57 is correspondingly decreased and the biasing spring 63 serves to 'move the contact arm 56 out of engagement with the segments 60 and62. This deenergizes the electromagnetic valve 52 and the latter operates to reestablish connection between the right hand side of auxiliary piston 21 and the braking cylinder air pipe 18. The reduction in pressure upon the right hand side of the piston-21 permits the piston 14 to move the application valve 15 to the right to increase the amount of air braking on the locomotive to a value which combined with the reduced electric braking will not slip the wheels of the locomotive.

Should the braking controller Br. C be moved to an operative position in which the excitation of the exciter shunt field windings f f is increased and a. correspondingly greater regenerative braking effect is ob tained upon the locomotive, the increased torque of the electric actuating mechanism 57 in conjunction with the force of the piston-55 may be suficient to move the contact arm 56 successively into engagement with the segments 60, 62 and 61. Upon engagement of segments 60 and 62 the electromagnetic valve 52 is energized to close communication between the braking cylinder air pipe 18 and the right hand side of piston 21, and upon engagement with the segment 61 the electromagnetic valve 53 is energized to admit air from the main reservoir M. R. directly to the right hand side of piston 21. The increased pressure upon piston 21 overcomes the opposing pressure upon piston 14 .and operates the latter to its extreme left hand position, thus opening the exhaust valve 41 to release air from the braking cylinder B. C. through the exhaust pipe 42. When' the amount of air braking on the locomotive is reduced to such an extent that combined with the existing electric braking there is no danger of slipping the wheels of the locomotive, the reduced pressure upon the piston 55 of the relay 54 permits the contactlarm 56 to move out of engagement with the segment 61. In this way the electromagnetic valve 53 is 'deenergized and cuts off the main reservoir pressure supply from the right hand side of piston 21 and traps a certain air pressure on the right'hand side of piston 21. 'This, in combination with the pressure on the leftihand side of piston tricbraking be built up to a high value, the contact 56 of the device 54 is held in the extreme right hand position, thereby keep Should the amount of regenerative elecof. piston 21. inpthe extreme left:hancl.position as shown ingjth' e contacts 60, 6 -1; an-d 62 closed and the valves 52 and 53, energized; These val-vesthen permit full main reservoir pres.- sureto remain applied to the right hand side This maintains the-valve 15 and keeps the pipe 1-8c0nnected through the passage- 42- to exhaust; thus entirely releasing the brakes: on: the locomotive; This condition will continue regardless of the amount or. application ofnthe air brakes on the; cars until the ielectricbraking is reduced bymanipulation vof the braking controller.

Eromvtheforegoingjtr will be evident that the; relay 54 operates to automaticallyrmain tain the 7 combined 5 air and electric braking v I eiitectsgupon the locomotive 'atasubsta-ntially ama-xinrum valuewhich, however, is insuf Eficient torslide'the wheels-of the locomotive.

If desired; the electromagnetic valve; 29 may be replaced by electromagnetic valves 4L6- V and l9" described in connection with Fig. 2

in" order to. automatically apply the air brakes -.uponthe cars, as W-ellIas. the locomotive, in case of. failure of the electric brakes While I have described the preferred-embodiments of theinvention in orderto explain theprinciPlesthereof, it Will be understood that the. invention is not limited to; the particular apparatus shown and may be carried out: by other. means.

What I claim as newzand desireto secure by Letters Patent of the United States, is:

' 1. In abraking system'for railway trains, the combination with separately and jointly operable air braking and electricbraking means, of control meansselectively operable to effect separate or joint operation of. said braking means, and automatic means. effective during separate operation of one t of saidbraking means for insuring application of the other braking means upon failure:

5 said one braking means;

2. Ina braking systemifor railway trains, the combination with separately and jointly operable air braking and electric braking means, of separate controllers therefor operable atwill to efi'ect separate orij oint application ofsaid brakmg means, of means under the joint control of said" separately mined application of one ot s'aid braking. -means upon failure of the other during operable controllers for insuring a predeterseparate application thereo'fif I 3'. In a braking system for railway trains, the combination of separately and jointly operable air braking means and electric braking-means, control means selectively operable to effect separate or simultaneous application of said braking means, and,

electrically controlled ai Operated I means efiective duringseparateapplication of the electric brakes forautomatically applying the i air1 brakes upon failure of the-electric;

brakes.

l. In a braking system, forrailway trains; I

the combinationwith means-for: applying air brakesto a railway trainunit and means. for applying, electric braking to the same-:;

unit, the two braking means beingeachnon of the electric brakes.

5. In a -braking. system for railwaytrains, the combination with separately and zjoi-ntly operable air braking and electric braking:

means, of a manually controlled valve'imechanismoperable at will to apply .theair brakes separately and jointly with the electric brakes,- and an electrically operated valves mechanism eflective during; separate appli-F cation of the electric brakes forqautomati cally applyingthe air brakes uponifailurerof the electric brakes.

6. In a braking system forrailWayatrains,i. the combination with separately and jointly: operable a1r braking and electric braking.

means, of -an air operated distributingjvalve a plurality of manual'control=valves-for controlling the operation of said distributing: valve, and independent electrically operated valve mechanism el'l'ective. during;separate operationof the electric brak-ingymeans tor:- automatically controlling said distributing 'for controlling the separate and joint appli cation oi diflercnt portions ot' thenairbrakes,

valve to 'e'li'ect' the joint applicationof the different. portions of said air bra'lres'uponfailure, of theelectricbrakes;

7. Ina brakingsystem for railW ay trains,

the combination with: separately operableair I braking means and electric braking ,means,

0f an automatic device arranged tobe.op.'

eratedVresponsively to failure of said electric brakingmeans, and an electromagnetic valve mechanism controlled. by said device-for an;

tomatically effecting a predetermined epplia cation of the said air braking ineans-upon operation of said device. J 8.- In a braking system forrailwaytrams,

the combination with manually operable means for applying a1r brakes to aqra-ilway train lllllll and manually operable means for applying electricbrakingto the vsame unit,'

the twobraking means beino' each normally separately operable, of an electroresponsi-ve device connected to be operated.respo-nsively to failure of the electric. braking means an" electrically controlled valve-mechanism for applying the airbrakes to the ,train unit'independentlyof said first means, and connec tions controlled by said first;means and said electroresponsive device for automaticallyenergizing said electromagnetic valve mechanism to effect a predeterminedapplication of the ail-brakes upon operation of said elecable air braking means and electric braking 1 means, of connections betweenthe two braking means for preventing the simultaneous operation thereofjwhen one of said braking means is applied above a predetermined value and for'automatically applying the other braking means when the application of said one means is reduced.

10. In a braking system forrailway trains, the combina ion with means for applying air brakes to a railway train unit and means for applying electric brakingto the same unit, the two braking means being each normally separately'operable, or" anelectrically controlled air operated device for preventing the simultaneous operation of said air braking nieans'when said electric braking means is applied above a predetermined value and for automatically effecting the application of said air braking means when the application of said electric braking means is reduced. I 1 i 11. In a braking system for railway trains the combination wit-h means for applying air brakes to a railway train unit and means for applying electric braking to the same unit, the two braking means being simultaneously operable when'the application of the electric braking is below a predetermined value, of an electrically controlled air operated device for automatically releasing the air brakes-when theelectric braking is'increased abovefsaid amount and for automatically reapplying the air brakes when the electric braking is subsequently reduced below said value. I I v 12. In a braking system for railway trains, the combination with simultaneously operable air' braking means and electric brakingmeans, of an electrically controlled air operated device associated with said air braking means and connected to be jointly controlled by said air and said electric braking means for preventing the simultaneous operation of the air braking means when the electric brakingmeans is applied above a a predeterminedvalue and-for automatically effecting the application of said air braking means when the application ofthe electric brakesis reduced below said value. a

' 18. In a braking system for railwaytrains, the combination with simultaneously operable air braking means and electric braking means, of connections between the two braking means for automatically varyingithe application of one or" said means inversely with variations in the other ofsaid 'means. i V a 14. In a braking system' for railway trains, the combination with simultaneously operable air braking means and electric braking means, of connections between the two braking means for preventing the simultaneous application thereof when one of said brakingvmeans is applied above a predeterand means for applying electric braking to the same unit, the two braking means being each normally separately operable, of connections between the two brakes permitting the simultaneous application of; a predetermined value of braking by the two brakes and for automatically varying the applica-V tion of one of the brakes inversely with variations 'in brake. V r

16. In a braking system for railway trains, the coinbination with means for applying air brakes to a railway train unit and means for applying electric braking to the same unit, the two braking means being each normally separately operable, of an the application of the other 7 automatic device arranged to'be operated responsively to the combined braking effect of the two braking means, andconnections 7 between the two brakes controlledby said device for permitting the simultaneous application of a predetermined value of braking by the brakes and for automatically varying the application of oneof the brakes inversely with Variations in the application of the-otherbrakeh a 17. In a braking system for railway trains, the combination with means for applying air brakes to a railway train unit and means for applying electric braking to the same unit,-t-he two braking means being each normally separately operable, of a combined electroresponsive and pressure responsive device arranged to be operated responsively to the combined braking efiect of said two braking means, an electrically controlled air opera-ted device associated with said air braking means for independently controlling the application and release thereof, and connections controlled by said combined airand pressure TGSPOIlSlVG device for controlling the said pressure operated device to permit the simultaneous,application ofa predeten mined value of braking by the saidair and electric braking meansand to automatically release said air brakes a predetermined,

amount upon a predetermined increase in the electric braking and apply said air brakes a predetermined amount upon a predetermined decrease in the electric braking. In witness whereof, I have hereunto set my hand this 29th day of May 1925. 7

- WILLIAM S. H. HAMILTON.

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